Journal of Geophysical Research: Biogeosciences最新文献

{"title":"Seasonal Effects of Soil Temperature and Soil Water Content on Upscaled Soil Respiration and Its Contribution to Ecosystem Respiration in Chaparral Shrublands","authors":"J. A. Montes,&nbsp;K. Lunneberg,&nbsp;M. N. Montemayor,&nbsp;B. M. Gillespie,&nbsp;W. C. Oechel","doi":"10.1029/2023JG007985","DOIUrl":"https://doi.org/10.1029/2023JG007985","url":null,"abstract":"<p>Chaparral, a semi-arid Mediterranean plant community, has the potential to act as a sink, which is an essential ecosystem to mitigate climate change. However, soil respiration (Rs) responses to meteorological variables remain uncertain in these regions, and no studies have quantified how much Rs attributes to Reco in chaparral shrublands. This study identifies the effects of soil temperature (Ts) and soil water content (SWC) on upscaled Rs and its contribution to Reco (Rs/Reco) in chaparral shrublands in Southern California between 2020 and 2021. Hourly Rs and net ecosystem exchange (NEE) were collected by automated chambers and the eddy covariance technique, respectively. Due to high daily variability and gaps in our data, 5-day averages were calculated to understand the effects of meteorological on Rs and Rs/Reco. First, we proposed that SWC was the primary driver of Rs regardless of the season, while Ts effects were prominent when SWC was sufficient. Secondly, we hypothesized Rs/Reco to vary seasonally, particularly due to Rs contributing less under dry conditions. Our results showed SWC to have a strong significant effect on Rs throughout the year, whereas Ts was only a significant control when the soil was wet and Ts was below 20°C. Monthly Rs/Reco was highest during January and February, likely due to the reduced aboveground respiration. While Rs/Reco was lowest when the soil was the driest. These findings improve our understanding of Rs response to climatic conditions and emphasize the importance of estimating Rs/Reco in chaparral shrublands.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 2","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023JG007985","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143186418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Machine Learning Reveals the Contrasting Roles of Rainfall and Canopy Structure Metrics on the Formation of Canopy Drip and Splash Throughfall","authors":"Kazuki Nanko,&nbsp;Delphis F. Levia,&nbsp;Shin'ichi Iida,&nbsp;Yoshinori Shinohara,&nbsp;Naoki Sakai","doi":"10.1029/2024JG008340","DOIUrl":"https://doi.org/10.1029/2024JG008340","url":null,"abstract":"<p>Throughfall is a significant majority of the total precipitation reaching the ground in forested areas. This study revealed biotic and abiotic factors influencing the throughfall generation process, with the throughfall partitioning into free throughfall, splash throughfall, and canopy drip created at foliar surface drip points (FSDPs) and occasional woody surface drip points (O-WSDPs), utilizing machine learning. Using a large-scale rainfall simulator, throughfall drops were simultaneously measured at 19 locations under a mix of deciduous and coniferous tree species in both foliated and unfoliated states. Random forest modeling showed that biotic factors, such as foliage amount, primarily affected the development and volume fraction of canopy drip in foliated trees. In contrast, for unfoliated trees, canopy drip volume fraction was mainly influenced by abiotic factors, including drop size and kinetic energy of open rainfall. The formation and volume fraction of splash throughfall were primarily influenced by abiotic factors for both foliated and unfoliated trees. From the comparison between the foliated and unfoliated states, the generation process of canopy drip was separately clarified between FSDPs and O-WSDPs. More and larger canopy drip was generated by more foliage with a more wetted canopy with less fluctuation at the FSDPs, whereas a less wetted canopy and/or higher drop impact energy generated more and larger canopy drip at O-WSDPs. This study underscores the importance of canopy structure and meteorological conditions in determining throughfall partitioning. The findings contribute to a nuanced understanding of rainwater redistribution in forest ecosystems.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 2","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143111532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploring the Significance of Chlorophyll Fluorescence-Based Photosynthetic Capacity in Gross Primary Productivity Simulations Across Diverse Ecosystems in China","authors":"Muhammad Amir,&nbsp;Bin Chen,&nbsp;Jinghua Chen,&nbsp;Shaoqiang Wang,&nbsp;Kai Zhu,&nbsp;Shiliang Chen,&nbsp;Ye Xia","doi":"10.1029/2023JG007889","DOIUrl":"https://doi.org/10.1029/2023JG007889","url":null,"abstract":"<p>Accurate estimation of gross primary productivity (GPP) plays a critical role in developing effective climate change policies. In addition to climatic factors, CO₂ levels, and leaf area index (LAI), GPP is also primarily regulated by the maximum rate of carboxylation (<i>V</i>_cmax) in ecosystem models. However, significant uncertainties in <i>V</i>_cmax measurements, along with its limited availability over larger geographical areas, hinder our ability to address scientific questions in context of increasing atmospheric CO₂ concentrations. Recently, solar-induced fluorescence (SIF) signals have been used as non-invasive way to monitor plant physiological processes. In this study, we utilized eddy covariance-based GPP and the Soil-Canopy Observation of Photosynthesis and Energy (SCOPE) model to infer <i>V</i>_cmax. We aimed to establish relationships between site-scale <i>V</i>_cmax and far-red solar-induced chlorophyll fluorescence yield (SIF_yield) to estimate photosynthetic capacity across diverse ecosystems in China from 2008 to 2010. Our findings revealed a robust relationship between SIF_yield and site-level <i>V</i>_cmax retrievals, with a coefficient of determination (<i>R</i>²) ranging from 0.36 to 0.74 (<i>p</i> &lt; 0.05) at biweekly (once every two weeks) intervals across all studied sites. Incorporating SIF_yield-derived <i>V</i>_cmax into the SCOPE model resulted in a 9% improvement in GPP simulation accuracy compare to using a constant <i>V</i>_cmax. Additionally, integration SIF_yield-derived <i>V</i>_cmax into the BEPS (Boreal Ecosystem Productivity Simulator) model demonstrated strong agreement between flux-based and simulated GPP values, further validating the accuracy of the estimated <i>V</i>_cmax in capturing ecosystem photosynthetic capacity. This study highlights the importance of utilizing SIF_yield to precisely quantify GPP estimates in the context of imminent climate change challenges.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 2","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143110762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Strong Effects of Increased Hydrostatic Pressure on Polysaccharide-Hydrolyzing Enzyme Activities in Coastal Seawater and Sediments","authors":"C. Chad Lloyd,&nbsp;John Paul Balmonte,&nbsp;Ronnie N. Glud,&nbsp;Carol Arnosti","doi":"10.1029/2024JG008417","DOIUrl":"https://doi.org/10.1029/2024JG008417","url":null,"abstract":"<p>Heterotrophic microorganisms are responsible for transforming and respiring a substantial fraction of the organic matter produced by phytoplankton in the surface ocean. Much of this organic matter is composed of polysaccharides, high-molecular weight (HMW) sugars. To initiate degradation of polysaccharides, microorganisms must produce extracellular enzymes of the right structural specificity to hydrolyze these complex structures. To date, most measurements of enzyme activities are made at in situ temperatures, but at atmospheric pressure. However, previous studies have shown that hydrostatic pressure can impact the functionality of enzymes. Since deep sea communities may be seeded by microbes from shallow waters, we aimed to determine if pressure affects the performance of enzymes from coastal waters. To determine the extent to which enzymatic activities of coastal microbial communities are affected by pressure, we quantified the degradation of seven polysaccharides under pressures ranging from 0.1 MPa (atmospheric) to 40 MPa (equivalent to 4,000 m). Enzyme activities of pelagic communities were inhibited with increased pressure, while enzyme activities of benthic microbial communities were more resistant to increased pressure. Addition of HMW organic matter resulted in communities with enzyme activities that were more resistant to increased pressure. However, the freely-dissolved enzymes (&lt;0.2 μm) produced by these communities were strongly inhibited by increased hydrostatic pressure, suggesting that the pressure-resistant enzymes were cell-surface attached. Because pressure inhibition of enzyme activities varied strongly by polysaccharide, we surmise that the structural complexity of a polysaccharide—and therefore the number of distinct enzymes required for hydrolysis—is likely closely associated with pressure inhibition.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 2","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143110735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Leaf Spectroscopy Reveals Drought Response Variation in Fagus sylvatica Saplings From Across the Species' Range","authors":"Dave Kurath,&nbsp;Sofia J. van Moorsel,&nbsp;Jolanda Klaver,&nbsp;Tis Voortman,&nbsp;Barbara Siegfried,&nbsp;Yves-Alain Brügger,&nbsp;Aboubakr Moradi,&nbsp;Ewa A. Czyż,&nbsp;Marylaure de La Harpe,&nbsp;Guido L. Wiesenberg,&nbsp;Michael E. Schaepman,&nbsp;Meredith C. Schuman","doi":"10.1029/2024JG008404","DOIUrl":"https://doi.org/10.1029/2024JG008404","url":null,"abstract":"<p>The common European beech (<i>Fagus sylvatica</i>), sensitive to prolonged drought, is expected to shift its distribution with climate change. To persist in novel environments, young trees rely on the capacity to express diverse response phenotypes. Several methods exist to study drought effects on trees and their diverse adaptive mechanisms, but these are usually destructive and challenging for the large sample numbers needed to investigate biological variation. We conducted a common garden experiment outdoors, but under controlled watering conditions, with 180 potted 2-year-old saplings from 16 beech provenances across the species' range, representing three distinct genetic clusters. Drought stress was simulated by interrupting irrigation and stomatal conductance and soil moisture were used to assess drought severity. We measured leaf reflectance of visible to short-wave infrared electromagnetic radiation to determine drought-induced changes in biochemical and structural traits derived from spectral indices and a model of leaf optical properties. We quantified changes in pigmentation, water balance, nitrogen, lignin, epicuticular wax, and leaf mass per area in drought-treated saplings, revealing differences in likely adaptive responses to drought. <i>F. sylvatica</i> saplings from the Iberian Peninsula showed signatures of greater drought resistance, that is, the least drought-induced change in spectrally derived traits related to leaf pigments and leaf water content. We demonstrate that high-resolution leaf spectroscopy is an effective and non-destructive tool to assess individual drought responses that can characterize functional intraspecific variation among young beech trees. Next, this approach should be scaled up to canopy-level or airborne spectroscopy to support drought response assessments of forests.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 2","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143110456","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Confirming the Primacy of Light Controlling Ammonium Removal in Response to Biofilm Colonization and Shade Using Experimental Streams","authors":"Anna E. S. Vincent,&nbsp;Jennifer L. Tank,&nbsp;Shannon L. Speir,&nbsp;Elise D. Snyder,&nbsp;Abagael N. Pruitt,&nbsp;Ursula H. Mahl,&nbsp;Robert O. Hall Jr.","doi":"10.1029/2024JG008259","DOIUrl":"https://doi.org/10.1029/2024JG008259","url":null,"abstract":"<p>The removal of riparian shading alters stream biogeochemical cycling by stimulating algal biofilms through the release of light limitation. Few studies have examined the combined effects of shading and biofilm growth on ammonium (NH₄⁺–N) and nitrate (NO₃⁻–N) removal in the same experiment. We quantified water column NH₄⁺–N and NO₃⁻–N removal using <i>n</i> = 176 short-term additions in four experimental streams over 2 years and assessed the influence of shading (shaded vs. open canopy) and biofilm colonization (early vs. late) on removal using a Bayesian three-level hierarchical model. First, we assessed the roles of biofilm and shade on NH₄⁺–N removal. Shading lowered NH₄⁺–N uptake velocity [<i>V</i>_<i>f</i>; slope: −0.45 (−0.69, −0.22)], while the effect of biofilm was too small to detect [0.06 (−0.18, 0.29)]. The following season, we compared NH₄⁺–N and NO₃⁻–N removal, and added night releases to estimate autotrophic and heterotrophic contributions to removal. Shading reduced NH₄⁺–N and NO₃⁻–N <i>V</i>_<i>f</i>, while the effect of biofilm often depended on shading. NH₄⁺–N <i>V</i>_<i>f</i> was higher than NO₃⁻–N <i>V</i>_<i>f</i> by 51% during the day and 38% at night, confirming preferential NH₄⁺–N removal. NO₃⁻–N <i>V</i>_<i>f</i> declined more between the Late-Open and Late-Shade phases compared to NH₄⁺–N, suggesting a stronger decline in NO₃⁻–N demand than for NH₄⁺–N with shade during late biofilm colonization. We found no strong diel shift in NH₄⁺–N or NO₃⁻–N demand. Results demonstrate the primacy of light on NH₄⁺–N and NO₃⁻–N removal in streams. Understanding how shading and biofilm colonization alter removal is critical as streams are vulnerable to the impacts of land use change.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 2","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008259","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143121455","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantifying the Effect of Petrogenic Carbon on SOC Turnover for Two Rocky Mountain Soils: When Are Petrogenic Carbon Corrections Required?","authors":"Elizabeth Williams,&nbsp;Corey Lawrence","doi":"10.1029/2023JG007838","DOIUrl":"https://doi.org/10.1029/2023JG007838","url":null,"abstract":"<p>Petrogenic organic carbon (OC_petro), derived from sedimentary rocks, is an often overlooked and poorly quantified source of soil organic carbon (SOC), which may influence measured or modeled SOC composition, age, and stability. In this study, we exploited differences in thermochemical stability between OC_petro and biogenic SOC (OC_bio) using stepped elemental analysis to quantify the fractional contribution of OC_petro to total SOC (f_petro), and we conducted a sensitivity analysis to estimate the effects of OC_petro on modeled SOC transit times and system ages. Specifically, we compared the effects of accounting for OC_petro inputs in SOC turnover modeling (using SoilR) for two montane meadow soils that are underlain by Cretaceous Mancos Shale. At these sites, we estimate that OC_petro comprises 7%–9% of the total SOC stock (f_petro = 0.07–0.09). However, accounting for OC_petro as a mixture of inert and passive C or as completely inert C had negligible effects on SOC transit times and system ages, suggesting that there is a threshold of OC_petro content under which there is minimal effect on calculated SOC turnover. Based on our sensitivity analysis, we estimate this threshold to be f_petro = 0.125, further supporting that the accurate calculation of OC_petro remains an important factor in estimating SOC turnover.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 2","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023JG007838","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143121454","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Depth-Distribution Patterns of Soil Organic Matter in the Tidal Marshes of the Venice Lagoon (Italy): Signatures of Depositional and Environmental Conditions","authors":"A. Puppin,&nbsp;D. Tognin,&nbsp;M. Ghinassi,&nbsp;E. Franceschinis,&nbsp;N. Realdon,&nbsp;M. Marani,&nbsp;A. D’Alpaos","doi":"10.1029/2024JG008327","DOIUrl":"https://doi.org/10.1029/2024JG008327","url":null,"abstract":"<p>Salt marshes are depositional landforms lying at the upper margin of intertidal environments. They provide a diverse range of valuable ecosystem services and yet are exceptionally vulnerable to climate change and human pressure. Salt marshes are intrinsically dynamic environments, shaped by complex feedback between hydrodynamic, morphological, and biological processes. Soil Organic Matter (SOM) has a crucial role within salt marsh environments, as on the one hand, its accumulation contributes to the build-up of marsh elevation which is necessary for marshes to keep pace with sea-level rise, and on the other it supports the high carbon sink potential of wetlands. To better understand variations in SOM depth distribution and further comprehend SOM drivers, we analyzed soil organic content in 10 salt marshes of the microtidal Venice Lagoon from 60 sediment cores to the depth of 1 m, relating SOM spatial and vertical patterns to the temporal and spatial variability of depositional sub-environments recorded in the study deposits. Our results suggest that changes in the depositional environment are of primary importance in determining organic matter depth distribution and caution is needed in SOM prediction at unsampled soil depths. We observed relationships between SOM vertical patterns and factors such as autochthonous and allochthonous organic inputs, sediment properties, relative sea level rise, fluvial inputs and wave action. Our findings emphasize the considerable carbon storage potential of marshes in intertidal environments and provide a conceptual framework for understanding the dynamics of SOM and their drivers, which can inform and enhance coastal management strategies.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 2","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008327","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143121251","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seasonal Variation and Key Controls of Groundwater Ammonium Concentrations in Hypoxic/Anoxic Riparian Sediments","authors":"Matthew G. Sena,&nbsp;Marc Peipoch,&nbsp;Bisesh Joshi,&nbsp;Md. Moklesur Rahman,&nbsp;Erin Peck,&nbsp;Arthur J. Gold,&nbsp;Jinjun Kan,&nbsp;Shreeram Inamdar","doi":"10.1029/2023JG007900","DOIUrl":"https://doi.org/10.1029/2023JG007900","url":null,"abstract":"<p>The seasonal controls of hydrology, temperature, hypoxia, and biogeochemical conditions for groundwater ammonium–N (NH₄⁺) concentrations are not well understood. Here we investigated these controls for riparian groundwaters located upstream of two milldams over a period of 4 years. Groundwater chemistry was sampled monthly while groundwater elevations, hydraulic gradients, and temperatures were recorded sub-hourly. Distinct seasonal patterns for NH₄⁺ were observed which differed among the wells. For wells that displayed a strong seasonal pattern, NH₄⁺ concentrations increased through the summer and peaked in October–November. These elevated concentrations were attributed to ammonification, suppression of nitrification, and/or dissimilatory nitrate reduction to ammonium (DNRA). These processes were driven by high groundwater temperatures, low hydraulic gradients (or long residence times), hypoxic/anoxic groundwater conditions, and increased availability of dissolved organic carbon as an electron donor. In contrast, NH₄⁺ concentrations decreased in the riparian groundwater from January to April during cool and wet conditions. A groundwater well with elevated total dissolved iron (TdFe) concentrations had elevated NH₄⁺ concentrations but displayed a muted seasonal response. In addition to hydrologic controls, we attributed this response to additional NH₄⁺ contribution from Fe-driven autotrophic DNRA and/or ammonification linked to dissimilatory Fe reduction. Understanding the temporal patterns and factors controlling NH₄⁺ in riparian groundwaters is important for making appropriate watershed management decisions and implementing appropriate best management practices.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 2","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143121254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biofilm Development, Senescence, and Benthic Substrate Influence Hyporheic Transport in Streams","authors":"Sabrina N. Volponi,&nbsp;Jennifer L. Tank,&nbsp;Anna E. S. Vincent,&nbsp;Elise D. Snyder,&nbsp;Abagael N. Pruitt,&nbsp;Diogo Bolster","doi":"10.1029/2024JG008225","DOIUrl":"https://doi.org/10.1029/2024JG008225","url":null,"abstract":"<p>Understanding fate and transport within fluvial systems requires accurate modeling of breakthrough curve (BTC) tails, which often display non-Fickian behaviors. However, it is unclear how anomalous processes relate to the physical and biological characteristics of the stream ecosystem. We use the Stochastic Mobile Immobile model (SMIM) to determine the impact of biofilm colonization among different substrate types on reach-scale transport velocity (V) and dispersion (D), rate of delivery to the subsurface (Λ), and retention within the subsurface (reflected by power law slope; <i>β</i>). During the summers of 2020 and 2021, we conducted a total of <i>n</i> = 42 Rhodamine-WT releases in four experimental streams lined with contrasting substrata (sand, pea gravel, cobble, and a three-way mix) at the Notre Dame Linked Experimental Ecosystem Facility (ND-LEEF) in Indiana (USA). To explore the effect of biofilm colonization, we conducted releases under artificially shaded, early and late biofilm development, and senescent biofilm conditions. We found that replicated releases under constant conditions consistently reproduced stream BTCs and modeled transport parameters. Biofilm abundance, biofilm status (living vs. dead), and substrate type produced significant variations in BTC shape and transport parameterizations. We found a non-linear relationship between algal biomass and V, where increases in biomass produced decreases in V at low biomass and increases in V at high biomass. Substrate type also predicted patterns in transport, with sand producing higher V, Λ, and <i>β</i> than larger substrata. These results suggest that substrate type acts as the primary driver and biofilm development the secondary control on transport in these stream systems.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 2","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143120701","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}